scholarly journals Diagnostics of common rail components based on pressure curves in the fuel rail

2018 ◽  
Vol 173 (2) ◽  
pp. 3-8
Author(s):  
Mirosław KARCZEWSKI ◽  
Krzysztof KOLIŃSKI

Majority of modern diesel engines is fitted with common-rail (CR) fuel systems. In these systems, the injectors are supplied with fuel under high pressure from the fuel rail (accumulator). Dynamic changes of pressure in the fuel rail are caused by the phenomena occurring during the fuel injection into the cylinders and the fuel supply to the fuel rail through the high-pressure fuel pump. Any change in this process results in a change in the course of pressure in the fuel rail, which, upon mathematical processing of the fuel pressure signal, allows identification of the malfunction of the pump and the injectors. The paper presents a methodology of diagnosing of CR fuel injection system components based on the analysis of dynamic pressure changes in the fuel rail. In the performed investigations, the authors utilized LabView software and a µDAC data acquisition module recording the fuel pressure in the rail, the fuel injector control current and the signal from the camshaft position sensor. For the analysis of the obtained results, ‘FFT’ and ‘STFT’ were developed in order to detect inoperative injectors based on the curves of pressure in the fuel rail. The performed validation tests have confirmed the possibility of identification of malfunctions in the CR system based on the pressure curves in the fuel rail. The ‘FFT’ method provides more information related to the system itself and accurately shows the structure of the signal, while the ’STFT’ method presents the signal in such a way as to clearly identify the occurrence of the fuel injection. The advantage of the above methods is the accessibility to diagnostic parameters and their non-invasive nature.

Author(s):  
Yong Yi ◽  
Aleksandra Egelja ◽  
Clement J. Sung

The development of a very high pressure diesel fuel injection system has been one of the key solutions to improve engine performance and to reduce emissions. The diesel fuel management in the injector directly affects how the fuel spray is delivered to the combustion chamber, and therefore affects the mixing, combustion and the pollutants formation. To design such a very high pressure diesel fuel injection system, an advanced CFD tool to predict the complex flow in the fuel injection system is required in the robust design process. In this paper, a novel 3D CFD dynamic mesh with cavitation model is developed to simulate the dynamic response of the needle motion of a diesel fuel injector corresponding to high common rail pressure and other dimensional design variables, coupling with the imbalance of the spring force and the flow force (pressure plus viscous force). A mixture model is used for cavitation resulting from high speed flow in fuel injector. Due to the lack of experimental data, the model presented in this paper is only validated by a limited set of experimental data. Required meshing strategy is also discussed in the paper.


Transport ◽  
2015 ◽  
Vol 31 (3) ◽  
pp. 305-311 ◽  
Author(s):  
Tomas Mickevičius ◽  
Stasys Slavinskas ◽  
Raimondas Kreivaitis

This paper presents a comparative experimental study for determining the effect of ethanol on functionality of a high pressure pump of the common rail fuel injection system. For experimental durability tests were prepared two identical fuel injection systems, which were mounted on a test bed for a fuel injection pump. One of the fuel injection systems was feed with diesel fuel; other fuel injection system was fuelled with ethanol–diesel fuel blend. A blend with 12% v/v ethanol and 88% v/v diesel fuel and low sulphur diesel fuel as a reference fuel were used in this study. To determine the effect of ethanol on the durability of the high pressure pump total fuel delivery performance and surface roughness of pump element were measured prior and after the test. Results show that the use of the ethanol–diesel blend tested produced a negative effect on the durability of the high pressure fuel pump. The wear of plungers and barrels when using ethanol–diesel fuel blend caused a decrease in fuel delivery up to 30% after 100 h of operation.


Author(s):  
Andrea Emilio Catania ◽  
Alessandro Ferrari

An innovative hydraulic layout for Common Rail (CR) fuel injection systems (FIS) without accumulator was further developed and assessed. The rail was removed and replaced by a high-pressure pipe junction to have faster dynamic system response during engine transients, smaller pressure induced stresses and reduced production costs. Compared to a commercial rail, whose internal volume ranges from 20 to 40 cm3, the junction provided a hydraulic capacitance of about 2 cm3 with the main function of connecting the pump delivery to the electroinjector feeding pipes. The modified injection system was realized and subjected to experimentation under engine-like working conditions on a high performance Moehwald-Bosch test bench. The injection performance of the new system with different hydraulic layouts was shown to be generally similar to those of a commercial CR system. Besides, for multiple injections, the new layout dynamics were substantially improved by a reduced dependence of the overall injected fuel amount on dwell-time (DT) during sequential injection events. This was achieved by selecting injector supplying pipes with an internal diameter and length out of the present production range. The results supported the findings that the rail capacitance was not a key parameter in pressure wave disturbance attenuation.


2013 ◽  
Vol 344 ◽  
pp. 182-185 ◽  
Author(s):  
Yong Zhi Zhang ◽  
Zhe Zuo ◽  
Bo Lan Liu

This paper proposed a kind of intelligent driving module based on the requirements of high pressure common rail fuel injection system. Many functions of this module were designed such as current multiply holding , boosting and energy recovering. This module occupies less microcontroller resources and makes injectors solenoid valve pull more smoothly. The experimental results show that the solenoid valves peak current can achieve to 20A within 0.1 ms and the storage capacitys potential was not changed significantly. This intelligent driving module could achieve the requirements of high pressure common rail driving circuit.


2020 ◽  
Author(s):  
Tom Tzanetakis ◽  
Mark Sellnau ◽  
Vincent Costanzo ◽  
Michael Traver ◽  
Tony Williams ◽  
...  

Author(s):  
Ke Zhang ◽  
Zhifeng Xie ◽  
Ming Zhou

Single-cylinder diesel engines usually employ mechanically actuated or time-type electrically controlled fuel injection systems. But due to the lack of flexibility to provide high pressure and fully varying injection parameters, fuel efficiency and emissions are poor. Although modern multi-cylinder engines have employed high pressure common rail fuel injection system for a long time, this technology has not been demonstrated in single-cylinder diesel engines. Due to the small installation space and little fuel injection amount of single cylinder diesel engine, high pressure common rail fuel injection system cannot be employed directly. In this study an electrically controlled high pressure fuel injection system of time-pressure-type (PTFS) for single-cylinder diesel engine was demonstrated. PTFS integrated the fuel pump and pressure reservoir (PR) to reduce installation space, which enabled it to match various kinds of single-cylinder diesel engines. However, the volume of the PR of PTFS is still limited, leading to obvious pressure fluctuation induced by periodic fuel pumping and injection. Pressure fluctuation might affect the stability and consistency of fuel injection, deteriorating the combustion and emissions of the engine further. This work established a mathematical model for the system, and studied the effect of the main parameters of the PR to the pressure fluctuations in the PR. The structure and dimensions of the system were optimized and a damping mechanism was proposed to reduce the pressure fluctuation. The optimized pressure fluctuation of PTFS achieved an acceptable level which can support steady and effective fuel injection. As a result, the fuel consumption efficiency and emission level of single cylinder diesel engine were enhanced.


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